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| [[File:Linear motor U-tube.svg|thumb|right|225px|[[Free-body diagram]] of a U-channel synchronous linear motor. The view is perpendicular to the channel axis. The two coils at centre are mechanically connected, and are energized in "[[quadrature phase|quadrature]]" (with a phase difference of 90° (π/2 [[radian]]s)). If the bottom coil (as shown) leads in phase, then the motor will move downward (in the drawing), and vice versa. (Not to scale)]]
| | If she develops naturally big boobs, she can have something else done with it," she states. What kind of results can I expect to see with a breast enlargement pump. It can also reduce the self esteem and self confidence of women but [http://www.lucky-house.info/ natural breast enlargement cream] not only enlarges the size of breast and prevents sagging. As a medicinal plant, Watercress has been traditionally considered a diuretic, expectorant, purgative, stimulant, stomachic and tonic. Feneugreek Seed Extract contains some of the main concentrations of the factory elements recommended by herbalists for breast enlargement. <br><br>Small, underdeveloped breasts may affect self-confidence. Some of the ingredients you will find in natural breast pills are fenugreek, wild yam and dong. This estrogen overproduction could be due to certain kind of tumors in the testicles or adrenal glands. Not only do implants frequently leak, necessitating further surgery, but they often just don't look very good. com recently picked up an NBC article that contains inaccurate information that Dr. <br><br>Silicone breast implants require longer incisions than saline-based implants. Examples of these herbs are non-medicinal substances which are derived from wild yam, fennel, and Dong Quai. The ingredients in this product are listed on the Food and Drug Administrations list of safe foods and none of the herbs used in it have any health warnings so it is a safe product to use. This procedure is most suitable for women who have small breasts small, underdeveloped breasts, which are asymmetric (smaller than the other), or breasts that have decreased in size after a woman has had children. Before undergoing the procedure, the surgeon will decide whether you are fit enough to undergo the procedure. <br><br>noticeable than a slightly misplaced round breast implant due to. 1) Some doctors will talk about bra cup size with you, but they will be sure to talk about it in a very general manner. At right: The location, shape, and size of the xiphoid process (click to enlarge). The trend of enlarging tits is going on increasing rapidly. this (you don't have to have your face in the pictures), then agree. <br><br>Mostly women who had that given preference to surgery pain to being hit by any vehicle. Surgery will only be considered, though, after some time has passed and the breasts haven't decreased in size. With fat grafting it is necessary to inject more because about 50-75% will be retained in the area and some will be absorbed by the body. These enhancement pills usually contain natural ingredients from herbal products that can directly affect a woman's body. News that she feels more sexy now as more curves have been added on her. <br><br>And among the three incisions, the transaxillary approach has the best scar cosmesis since it is concealed and nipple sensation is well preserved. One advantage of saline implants is that the liquid is harmlessly absorbed by the body if an implant ruptures. Since human infants do not have a protruding jaw like our ancestors and the other primates, the infant's nose might be blocked by a flat female chest while feeding. Moreover, most do contain the delivery systems required to bring stimulation extracts across the skin barriers, even if they do contain adequate amount of those herbal extracts. They have an opportunity to have the breasts that they have always dreamed about having. |
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| A '''linear motor''' is an [[electric motor]] that has had its [[stator]] and [[rotor (electric)|rotor]] "unrolled" so that instead of producing a [[torque]] ([[rotation]]) it produces a linear [[force]] along its length. The most common mode of operation is as a [[Lorentz force|Lorentz]]-type actuator, in which the applied force is [[linear equation|linearly proportional]] to the [[electric current|current]] and the [[magnetic field]] <math>(\vec F = I \vec L \times \vec B)</math>.
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| Many designs have been put forward for linear motors, falling into two major categories, low-acceleration and high-acceleration linear motors. Low-acceleration linear motors are suitable for [[maglev train]]s and other ground-based transportation applications. High-acceleration linear motors are normally rather short, and are designed to accelerate an object to a very high speed, for example see the [[coilgun]].
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| High-acceleration motors are usually used for studies of [[hypervelocity]] collisions, as [[weapon]]s, or as [[mass driver]]s for [[spacecraft propulsion]]. They are usually of the AC '''linear induction motor''' (LIM) design with an active [[three-phase]] winding on one side of the air-gap and a passive conductor plate on the other side. However, the direct current [[homopolar motor|homopolar]] linear motor [[railgun]] is another high acceleration linear motor design. The low-acceleration, high speed and high power motors are usually of the '''linear synchronous motor''' (LSM) design, with an active winding on one side of the air-gap and an array of alternate-pole magnets on the other side. These magnets can be permanent magnets or energized magnets. The [[Shanghai Transrapid]] motor is an LSM.
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| ==Types==
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| [[File:Linear motor by Zureks.jpg|thumb|left|A prototype of linear motor with visible separate coils]]
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| ===Induction motor===
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| {{main|Linear induction motor}}
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| In this design, the force is produced by a moving linear [[magnetic field]] acting on conductors in the field. Any conductor, be it a loop, a coil or simply a piece of plate metal, that is placed in this field will have [[eddy current]]s [[electromagnetic induction|induced]] in it thus creating an opposing magnetic field, in accordance with [[Lenz's law]]. The two opposing fields will repel each other, thus creating motion as the magnetic field sweeps through the metal.
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| ===Synchronous motor===
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| [[File:Linearmotorprinzip.png|thumb|right|Synchronous linear motors are straightened versions of permanent magnet rotor motors]]
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| In this design the rate of movement of the magnetic field is controlled, usually electronically, to track the motion of the rotor. For cost reasons synchronous linear motors rarely use commutators, so the rotor often contains permanent magnets, or soft iron. Examples include [[coilgun]]s and the motors used on some [[maglev]] systems, as well as many other linear motors.
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| ===Homopolar===
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| [[File:Railgun-1.svg|thumb|left|Railgun schematic]]
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| {{main|Railgun}}
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| In this design a large current is passed through a metal sabot across sliding contacts that are fed from two rails. The magnetic field this generates causes the metal to be projected along the rails.
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| {{clear}}
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| ===Piezo electric===
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| [[File:Piezomotor type inchworm.gif|thumb|right|Piezoelectric motor action]]
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| {{main|Piezoelectric motor#Stepping actions}}
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| Piezoelectric drive is often used to drive small linear motors.
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| {{clear}}
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| ==History==
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| [[Image:JFK AirTrain.agr.jpg|thumb|left|225px|[[Bombardier Advanced Rapid Transit|ART]] trains propel themselves using an aluminium induction strip placed between the rails.]]
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| ===Low acceleration===
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| The history of linear electric motors can be traced back at least as far as the 1840s, to the work of [[Charles Wheatstone]] at [[King's College London|King's College]] in London,<ref>{{cite web|url=http://www.kcl.ac.uk/college/history/people/wheatstone.html |title=Charles Wheatstone - College History - King's College London |publisher=Kcl.ac.uk |date= |accessdate=2010-03-01}}</ref> but Wheatstone's model was too inefficient to be practical. A feasible linear induction motor is described in the {{US patent|782312}} ( 1905 - inventor Alfred Zehden of Frankfurt-am-Main ), for driving trains or lifts. The German engineer [[Hermann Kemper]] built a working model in 1935.<ref>http://cem.colorado.edu/archives/fl1997/thor.html</ref> In the late 1940s, Dr. [[Eric Laithwaite]] of [[University of Manchester|Manchester University]], later Professor of Heavy Electrical Engineering at [[Imperial College]] in [[London]] developed the first full-size working model. In a single sided version the magnetic repulsion forces the conductor away from the stator, levitating it, and carrying it along in the direction of the moving magnetic field. He called the later versions of it [[magnetic river]].
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| [[File:Linear Motor of Toei Ōedo Line.jpg|thumb|right|200px|A linear motor for trains running Toei Oedo line]]
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| Because of these properties, linear motors are often used in [[magnetic levitation|maglev]] propulsion, as in the Japanese [[Linimo]] [[magnetic levitation train]] line near [[Nagoya]]. However, linear motors have been used independently of magnetic levitation, as in [[Bombardier Transportation|Bombardier]]'s [[Bombardier Advanced Rapid Transit|Advanced Rapid Transit]] systems worldwide and a number of modern Japanese subways, including [[Tokyo]]'s [[Toei Oedo Line]].
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| Similar technology is also used in some [[roller coaster]]s with modifications but, at present, is still impractical on street running [[tram]]s, although this, in theory, could be done by burying it in a slotted conduit.
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| Outside of public transportation, vertical linear motors have been proposed as lifting mechanisms in deep [[mining|mine]]s, and the use of linear motors is growing in [[motion control]] applications. They are also often used on sliding doors, such as those of [[low floor]] [[tram]]s such as the [[Citadis]] and the [[Eurotram]]. Dual axis linear motors also exist. These specialized devices have been used to provide direct ''X''-''Y'' motion for precision laser cutting of cloth and sheet metal, automated [[Technical drawing|drafting]], and cable forming. Most linear motors in use are LIM (linear induction motor), or LSM (linear synchronous motor). Linear DC motors are not used due to higher cost and linear SRM suffers from poor thrust. So for long run in traction LIM is mostly preferred and for short run LSM is mostly preferred.
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| [[File:Linear motor platen surface.jpg|thumb|right|Close-up of the flat passive conductor surface of a motion control linear motor]]
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| ===High acceleration===
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| High-acceleration linear motors have been suggested for a number of uses.
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| They have been considered for use as [[weapon]]s, since current [[armour-piercing]] ammunition tends to consist of small rounds with very high [[kinetic energy]], for which just such motors are suitable. Many amusement park [[roller coasters]] now use linear induction motors to propel the train at a high speed, as an alternative to using a [[lift hill]]. The United States Navy is also using linear induction motors in the [[Electromagnetic Aircraft Launch System]] that will replace traditional [[steam catapult]]s on future aircraft carriers. They have also been suggested for use in [[spacecraft propulsion]]. In this context they are usually called [[mass driver]]s. The simplest way to use mass drivers for spacecraft propulsion would be to build a large mass driver that can accelerate cargo up to [[escape velocity]], though [[reusable launch system|RLV]] launch assist like [[StarTram]] to [[low earth orbit]] has also been investigated.
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| High-acceleration linear motors are difficult to design for a number of reasons. They require large amounts of [[energy]] in very short periods of time. One rocket launcher design<ref>[http://www.coilgun.info/theory/electroguns.htm ]{{dead link|date=March 2010}}</ref> calls for 300 GJ for each launch in the space of less than a second. Normal [[electrical generator]]s are not designed for this kind of load, but short-term electrical energy storage methods can be used. [[Capacitors]] are bulky and expensive but can supply large amounts of energy quickly. [[Homopolar generator]]s can be used to convert the kinetic energy of a [[flywheel]] into electric energy very rapidly. High-acceleration linear motors also require very strong magnetic fields; in fact, the magnetic fields are often too strong to permit the use of [[superconductivity|superconductors]]. However, with careful design, this need not be a major problem.
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| Two different basic designs have been invented for high-acceleration linear motors: [[railgun]]s and [[coilgun]]s.
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| Example : Maglev
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| == Usage ==
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| Linear motors are widely used. One of the major uses of linear motors is for propelling the shuttle in [[loom]]s.
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| Linear motors have been used for sliding doors and various similar actuators.
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| Linear motors are sometimes used to create rotary motion, for example, they have been used at observatories to deal with the large radius of curvature.
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| A linear motor has been used for accelerating cars for [[crash test]]s.<ref>http://books.google.com/books?id=pgAAAAAAMBAJ&lpg=PA64&ots=h1ZnQLJny2&dq=crash%20testing%20linear%20motor&pg=PA64#v=onepage&q=crash%20testing%20linear%20motor&f=false</ref>
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| [[Image:Guangzhou Metro Line 5 vehicle.jpg|thumb|Guangzhou Metro L5 vehicle made by CSR [[Sifang Locomotive and Rolling Stock]] and [[Kawasaki Heavy Industries]]]]
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| === Train propulsion ===
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| ====Conventional rails====
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| All applications are in [[rapid transit]].[[Image:Gzmtr4linerail.jpg|thumb|Guangzhou Metro L4 vehicle made by CSR [[Sifang Locomotive and Rolling Stock]] & [[Kawasaki Heavy Industries]]]]
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| * [[Bombardier Advanced Rapid Transit|Bombardier ART]]:
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| ** [[Airport Line, Beijing Subway|Airport Express]] in Beijing (opened 2008)
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| ** [[AirTrain JFK]] in New York (opened 2003)
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| ** [[Detroit People Mover]] in Detroit (using ICTS) opened 1987
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| ** [[EverLine Rapid Transit System]] in Yongin (under construction)
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| ** [[Kelana Jaya Line]] in Kuala Lumpur (opened 1998)
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| ** [[Scarborough RT]] in Toronto (using [[UTDC]]'s (predecessor) [[Intermediate Capacity Transit System|ICTS]] technology - opened 1985)
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| ** [[UTDC]] ICTS test track in [[Millhaven, Ontario]]
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| ** [[Vancouver SkyTrain|SkyTrain]] in Vancouver ([[Expo Line (TransLink)|Expo Line]] (using ITCS) opened 1985 and [[Millennium Line]] opened in 2002)
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| **Beijing Subway Capital Airport Track (opened 2008)
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| * Several subways in Japan and China, built by [[Kawasaki Heavy Industries]]:
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| **Limtrain in [[Saitama, Saitama|Saitama]] (short-lived demonstration track, 1988)
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| **[[Nagahori Tsurumi-ryokuchi Line]] in Osaka (opened 1990)
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| **[[Toei Ōedo Line]] in Tokyo (opened 2000)
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| **[[Kaigan Line]] in Kobe (opened 2001)
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| **[[Nanakuma Line]] in Fukuoka (opened 2005)
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| **[[Imazatosuji Line]] in Osaka (opened 2006)
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| **[[Green Line (Yokohama)|Green Line]] in Yokohama (opened 2008)
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| **[[Sendai Subway Tōzai Line]] in [[Sendai]], Japan (under construction, opening 2015)
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| ** Line 4 of [[Guangzhou Metro]] in [[Guangzhou]], China (opened 2005).<ref>{{cite web|url=http://www.urbanrail.net/as/guan/guangzhou.htm |title=> Asia > China > Guangzhou Metro |publisher=UrbanRail.Net |date= |accessdate=2010-03-01}}</ref>
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| ** Line 5 of Guangzhou Metro in Guangzhou, China (open in December 2009).
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| ** Line 6 of Guangzhou Metro in Guangzhou, China (open in December 2013).
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| Both the Kawasaki trains and Bombardier's ART have the active part of the motor in the cars and use [[Overhead lines|overhead wires]] (Japanese subways<ref>{{cite web|url=http://home.inet-osaka.or.jp/~teraoka/old/tera98/ml98edit.htm |title=Adoption of Linear Motor Propulsion System for Subway |publisher=Home.inet-osaka.or.jp |date= |accessdate=2010-03-01}}</ref><ref>[http://www.hitachi.com/csr/highlight/activities/2007/act0701/index.html ]{{dead link|date=March 2010}}</ref>) or a [[third rail]] (ART<ref>{{cite web|date= November 10, 2006 |url=http://transit.toronto.on.ca/subway/5107.shtml |title=The Scarborough Rapid Transit Line - Transit Toronto - Content |publisher=Transit Toronto |accessdate=2010-03-01}}</ref>) to transfer power to the train.
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| ====Monorail====
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| {{Refimprove|date=July 2009}}
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| * There is at least one known monorail system which is '''not''' magnetically levitated, but nonetheless uses linear motors. This is the [[Moscow Monorail]]. Originally, traditional motors and wheels were to be used. However, it was discovered during test runs that the proposed motors and wheels would fail to provide adequate traction under some conditions, for example, when ice appeared on the rail. Hence, wheels are still used, but the trains use linear motors to accelerate and slow down. This is possibly the only use of such a combination, due to the lack of such requirements for other train systems.
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| * The [[TELMAGV]] is a prototype of a monorail system that is also not magnetically levitated but uses linear motors.
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| ====Magnetic levitation====
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| {{Main|Maglev (transport)}}
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| [[File:Birmingham International Maglev.jpg|thumb|The Birmingham International Maglev shuttle]]
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| * High-speed trains:
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| ** [[Transrapid]]: first commercial use in [[Shanghai Maglev|Shanghai]] (opened in 2004)
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| ** [[SCMaglev]], under test in Japan
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| * Rapid transit:
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| ** Birmingham Airport, UK (opened 1984, closed 1995)
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| ** [[M-Bahn]] in Berlin, Germany (opened in 1989, closed in 1991)
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| ** Daejeon EXPO, Korea (ran only 1993)<ref>{{cite web|url=http://maglev.de/index.php?en_korea |title=The International Maglevboard |publisher=Maglev.de |date= |accessdate=2010-03-01}}</ref>
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| ** [[HSST]]: [[Linimo]] line in Aichi Prefecture, Japan (opened 2005)
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| ===Amusement rides===
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| There are many roller coasters throughout the world that use LIM to accelerate the ride vehicles. The first being ''Flight of Fear'' at [[Kings Island]] and [[Kings Dominion]]. Both opened in 1996.
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| e.g.:
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| * [[Blue Fire]] - Where the LIM accelerates the train from 0 to 100 km/h in 2.5 s.
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| * [[California Screamin']] - Roller coaster LIM application
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| * [[Maverick (roller coaster)|Maverick]] - A roller coaster LSM application
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| * [[Tomorrowland Transit Authority]] - Slow ride LIM application
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| * [[Tower of Terror (roller coaster)|Dreamworld, Australia]] - LSM reverse freefall roller coaster
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| ===Aircraft Launching===
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| * [[Electromagnetic Aircraft Launch System]]
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| ===Proposed & research===
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| * [[Launch loop]] - A proposed system for launching vehicles into space using a linear motor powered loop
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| * [[StarTram]] - Concept for a linear motor on extreme scale
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| * [[Tether propulsion#Tether cable catapult system|Tether cable catapult system]]
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| * [[Research Test Vehicle 31]] - A hovercraft-type vehicle guided by a track
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| == See also ==
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| * [[Linear actuator]]
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| * [[Maglev]]
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| * [[Online Electric Vehicle]]
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| * [[Sawyer motor]]
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| * [[Tubular linear motor]]
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| == References ==
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| {{Reflist}}
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| ==External links==
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| * [http://www.instructables.com/id/Electromagnetic-Actuator/?ALLSTEPS Design equations, spreadsheet, and drawings]
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| * [http://www.ms-motor.com/technical-support/motor-torque-calculation Motor torque calculation]
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| * [http://web.archive.org/web/20080516063621/http://www.coilgun.info/theory/electroguns.htm Overview of Electromagnetic Guns]
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| * [http://ariwatch.com/VS/VoiceCoils/ Voice Coil Actuators]
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| <!--spacing, please do not remove-->
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| {{Electric motor}}
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| {{DEFAULTSORT:Linear Motor}}
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| [[Category:Electric motors]]
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| [[Category:Automation]]
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| [[Category:English inventions]]
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| [[Category:Magnetic propulsion devices| ]]
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| [[Category:Linear motion]]
| |
If she develops naturally big boobs, she can have something else done with it," she states. What kind of results can I expect to see with a breast enlargement pump. It can also reduce the self esteem and self confidence of women but natural breast enlargement cream not only enlarges the size of breast and prevents sagging. As a medicinal plant, Watercress has been traditionally considered a diuretic, expectorant, purgative, stimulant, stomachic and tonic. Feneugreek Seed Extract contains some of the main concentrations of the factory elements recommended by herbalists for breast enlargement.
Small, underdeveloped breasts may affect self-confidence. Some of the ingredients you will find in natural breast pills are fenugreek, wild yam and dong. This estrogen overproduction could be due to certain kind of tumors in the testicles or adrenal glands. Not only do implants frequently leak, necessitating further surgery, but they often just don't look very good. com recently picked up an NBC article that contains inaccurate information that Dr.
Silicone breast implants require longer incisions than saline-based implants. Examples of these herbs are non-medicinal substances which are derived from wild yam, fennel, and Dong Quai. The ingredients in this product are listed on the Food and Drug Administrations list of safe foods and none of the herbs used in it have any health warnings so it is a safe product to use. This procedure is most suitable for women who have small breasts small, underdeveloped breasts, which are asymmetric (smaller than the other), or breasts that have decreased in size after a woman has had children. Before undergoing the procedure, the surgeon will decide whether you are fit enough to undergo the procedure.
noticeable than a slightly misplaced round breast implant due to. 1) Some doctors will talk about bra cup size with you, but they will be sure to talk about it in a very general manner. At right: The location, shape, and size of the xiphoid process (click to enlarge). The trend of enlarging tits is going on increasing rapidly. this (you don't have to have your face in the pictures), then agree.
Mostly women who had that given preference to surgery pain to being hit by any vehicle. Surgery will only be considered, though, after some time has passed and the breasts haven't decreased in size. With fat grafting it is necessary to inject more because about 50-75% will be retained in the area and some will be absorbed by the body. These enhancement pills usually contain natural ingredients from herbal products that can directly affect a woman's body. News that she feels more sexy now as more curves have been added on her.
And among the three incisions, the transaxillary approach has the best scar cosmesis since it is concealed and nipple sensation is well preserved. One advantage of saline implants is that the liquid is harmlessly absorbed by the body if an implant ruptures. Since human infants do not have a protruding jaw like our ancestors and the other primates, the infant's nose might be blocked by a flat female chest while feeding. Moreover, most do contain the delivery systems required to bring stimulation extracts across the skin barriers, even if they do contain adequate amount of those herbal extracts. They have an opportunity to have the breasts that they have always dreamed about having.